Jp. Eiserich et al., MOLECULAR MECHANISMS OF DAMAGE BY EXCESS NITROGEN-OXIDES - NITRATION OF TYROSINE BY GAS-PHASE CIGARETTE-SMOKE, FEBS letters, 353(1), 1994, pp. 53-56
Nitric oxide (nitrogen monoxide, (NO)-N-.) plays important physiologic
al roles, but an excess can be toxic. (NO)-N-. is present in cigarette
smoke (CS) at up to 500 ppm, and probably represents one of the great
est exogenous sources of (NO)-N-. to which humans are exposed. We show
here that gas-phase CS is capable of converting tyrosine to 3-nitroty
rosine (3-NO2-Tyr) and dityrosine, to an extent dependent on time of e
xposure and pH. Glutathione, ascorbic acid and uric acid decreased the
CS-induced formation of 3-NO2-Tyr and dityrosine. We suggest that nit
rogen oxides in CS can modify proteins in the respiratory tract and ma
y contribute to CS toxicity.